Published: Sat, January 05, 2019
Research | By Wilma Wheeler

NASA space probe 'phones home' in landmark mission to solar system's edge

NASA space probe 'phones home' in landmark mission to solar system's edge

The first detailed images beamed back by NASA's New Horizons spacecraft after its historic flyby of Ultima Thule - the most distant and possibly the oldest space object ever explored - show that the icy "worldlet" resembles a reddish snowman, the USA space agency said on January 3.

NASA's New Horizons mission flew by the object early on January 1, and the maneuver's science data will reach Earth over the course of almost two months.

About the size of a city, Ultima Thule has a mottled appearance and is the color of boring brick, probably because of the effects of radiation bombarding the icy surface, with brighter and darker regions.

Color images from New Horizons revealed that Ultima Thule, like other Kuiper Belt objects, has a dark reddish hue, although it is thought to be primarily made of ice.

The object has two lobes, with the larger one now taking the name Ultima and the smaller becoming Thule.

Scientists weren't able to confirm the flyby until several hours later.

New Horizons zoomed past the small celestial object is known as Ultima Thule 3 ½ years after its spectacular brush with Pluto.

The New Horizons spacecraft sends the images of Ultima Thule which is an asteroid and is beyond the solar system.

Among the images the scientists are hoping to receive are "higher resolution views" and pictures taken when the sun is at a better angle for viewing Ultima Thule.


The team also discovered the region of Ultima Thule corresponding to the snowman's neck is one of its brightest parts, suggesting fine grain material may have rolled there due to steep slopes and gravity.

As the spacecraft transmits dozens more data sets to Earth, "we'll write new chapters in the story of Ultima Thule-and the Solar System", according to New Horizons Project Manager Helene Winters.

Researchers at the Johns Hopkins University Applied Physics Laboratory in Laurel, Maryland, where New Horizons is operated, were up late, working to transform those bits of data into the first high-resolution image of a Kuiper belt object. Unlike comets and other objects that have been altered by the sun over time, Ultima Thule is in its pure, original state: It's been in the deep-freeze Kuiper Belt on the fringes of our solar system from the beginning.

New Horizons principal investigator Alan Stern (centre) of the Southwest Research Institute celebrates the breakthrough with other mission team members.

The black-and-white photo was taken from about 30,000 miles away, as New Horizons sped toward its target at 32,000 miles per hour. More than 100 scientists, including Heidi B. Hammel, a planetary scientist and a media liaison for the science team, gathered at 8 p.m. for a look.

Planetary scientists have never before seen a close-up of an object like Ultima Thule.

"The term, Ultima Thule, which is very old, many centuries old, possibly a thousand years old, is a wonderful meme for exploration, and that's why we chose it", Stern said.

Clearer images and more confident assessments of Ultima Thule's surface composition and topography are expected in the immediate days ahead.

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